This was my last experience looking for kecap manis, about a month ago at the Asian grocery store on the east side of Spadina, just north of Dundas.
Me (to third clerk, first 2 passed me off once they heard me speaking English): Do you have any kecap manis?
Me: No (trying hard to pronounce clearly), ke-cap ma-nis.
Him (walks me over to aisle and points to Heinz ketchup).
Me (shaking my head, smiling): No, kecap manis.
New person approaches...
Me: I'm trying to find kecap manis.
Me: No, kecap manis.
Her: Ah, mayonnaise!
Me: No, kecap manis. It's an Indonesian sauce, sort of like a sweet thick soy sauce.
Her (walks me over to another aisle, points to ABC kecap manis): Kecap manis.
Me: Yes, yes, that's it. Thank you so much.
Her (wagging her finger at me somewhat sternly, though not unfriendly): Kecap manis. Not mayonnaise!
Me: Right. Got it. Thanks.
Anyway, always an amusing outing. It was the ubiquitous ABC brand, though I have to say it was a bit different than the way I remembered it from Indonesia - a little thicker, not quite the same taste. Maybe my memory (along with my pronunciation) is failing me. Anyway, good luck on your quest.
Most good Asian grocery stores should have it. T&T has it in their location here in Mississauga, so I'm sure they'd have it in their other locations. I've seen a couple of different types of ABC brand, one I think has a blue label, but I always buy the one with the red label. It should cost around $1.50-$2.99 (I can't remember how much I pay...I think it's $1.89, not at T&T). It's great mixed with sambal oelek for a delicious hot and sweet taste.
T&T should have it. In the past, I've seen it downstairs at the St Lawrence (south) Market in the smaller of the spices/sauces stores, but it's cheaper in Chinatown. Look for ABC Brand Ketjap Manis. It is the Heinz Ketchup of Indonesia. It's everywhere there. Which is a funny thing, because Heinz bought the brand.